Yasser Arafat's sudden health crisis has again raised the question, in Palestinian circles as in the wider world, of who ultimately will replace the 75-year-old president - and whether the succession will be smooth or volatile.

Until now, Palestinian politicians have been reluctant to speak openly about the next leader, mainly because Mr Arafat would not allow it but also because it would be seen as a betrayal, a surrender to the Israeli prime minister, Ariel Sharon, who has been successful in marginalising him.

Mr Arafat's ill-health, which has dogged him for years, was apparent only a fortnight ago when he met a small group of British journalists. He frequently rambled from issue to issue, and raised odd conspiracy theories that ranged from Iran to Chile.

The sudden deterioration in his condition came less than 24 hours after his arch-rival, Mr Sharon, pushed through the Knesset his planned withdrawal from the Gaza Strip last year. That offered a chance to break the Middle East stalemate.

If Mr Arafat is unable to continue as leader of the Palestinians, that too will change the politics of the region. The US and Israel, and latterly Britain, have refused to work with him, claiming he is unreliable and untrustworthy.

His successor could come from one of the new generation of politicians, either the younger Palestinians who came to the West Bank and Gaza with him from exile in Tunis 10 years ago, or the generation that was brought up in the West Bank and Gaza and led the first intifada in 1987 and participated or led the second one that began in September 2000.

The successor could be a figure such as the existing prime minister or finance minister, or one of the warlords, such as Jibril Rajoub or Mohammed Dahlan, or Marwan Barghouti, at present in jail in Israel.

But the succession might not be that simple. Groups outside Mr Arafat's Fatah organisation might want a claim on leadership, not least the Islamist organisation Hamas that dominates life in Gaza.

Hamas and Islamic Jihad have been careful not to attack Mr Arafat but might not feel the same trepidation about confronting his potential successor.

Mr Arafat's glory days were as a revolutionary leader but he has been less successful as an administrator of the West Bank and Gaza after the Oslo agreement with Israel. His Palestinian Authority became synonomous with corruption and lost much popular support.

He has expressed scepticism about Mr Sharon's Gaza withdrawal plan, claiming that the Israelis would keep Gaza as an open prison and that Israel remained intent on expanding its hold on the West Bank. A successor would probably share the same view, but might be more inclined to take what is on offer and try to make the most of it, something Mr Arafat was reluctant to do.

Hamas was swift to claim that the Israeli parliament's vote to pull Jewish settlers out of the battered Gaza Strip was a victory for Palestinian resistance.

But Palestinian leaders say there is little to cheer even if Mr Sharon carries through his pledge to remove about 7,500 settlers and the army from one part of Palestinian territory.

"We should look on it as rearranging the occupation in a way that is more comfortable to the occupier," said one Palestinian cabinet minister, Ghassan Khatib. "It's clear that Sharon is linking the withdrawal from Gaza to consolidation of occupation in the West Bank. It's not going to be realised."

The Palestinian foreign minister, Nabil Shaath, said he feared that the Gaza withdrawal would be Israel's "first and last" pullout.

"The Palestinian people will be happy when they see them withdraw from all of Palestine," he said.

Mr Sharon has justified taking unilateral action on the grounds that there is no one to negotiate with on the Palestinian side because he says Yasser Arafat "will not fight terror".

A new, more robust leader could neutralise that argument, though no Palestinian leader would find it easy to take on the militants without risking all-out civil war.